In the automotive industry, vehicles are mass-produced using complex assembly line processes, in which each vehicle is assembled together as it passes through a plurality of different assembly stations. Separate assembly lines may also be provided for assembling vehicle sub-assemblies and components, which are subsequently incorporated into one of the vehicles that is being assembled on the main assembly line. Typically, a single type of vehicle includes many different types of clamshell components, which may be used in engine cradles, as frame cross-members, etc.
In the case of clamshell components, typically upper and lower shells, which may or may not be substantially identical to each other, are aligned and joined together along overlapping edge portions or flanges. A few specific and non-limiting examples of common joining techniques include metal inert gas (MIG) welding and spot welding. Different types of clamshell components may have different lengths, different contours along one or more of the outer surfaces, different spacing between piercings, etc. In order to ensure that the upper and lower shells are joined securely one to the other, overlapping edge portions of the upper and lower shells are pressed together using squeezers that are customized for the particular component being formed, and the joining is performed during squeezing. In particular, the squeezers are customized to conform closely to the contours along the overlapping edge portions of the upper and lower shells, so as to avoid forming any gaps along the resulting joint.
Prior art strongback machines have squeezers that squeeze the clamshell components along the weld face, in order to close gaps in clamshell components as described above. These machines are custom-built, and are not re-usable for different components. In particular, such strongback machines do not accommodate variable widths, heights, and/or lengths for manufacturing various clamshell components. Of course, high tooling costs are associated with the purchase of custom tools for forming each of a plurality of different clamshell components. Further, whenever a different clamshell component needs to be manufactured there is lost production time associated with switching out one strongback machine and replacing it with a different strongback machine that supports production of the different clamshell component. Further still, storing a plurality of different strongback machines consumes floor-space within manufacturing facilities and may contribute to unsafe working conditions.
It is desirable to provide a clamshell assembly fixture that overcomes at least some of the above-mentioned limitations of the prior art.